Chemotherapy and/or radiotherapy is effective at destroying tumors because it targets the most rapidly growing tissues. The mechanism involves impairment of DNA synthesis or interference with metabolic processes required for rapidly dividing cells. While tumor cells are selectively targeted by anticancer treatments, the most rapidly growing tissues of the host are also susceptible to these effects. The mucosal epithelium of the alimentary tract has one of the most rapid rates of cell division of any body tissue, and is therefore a major site of toxicity for anticancer regimens.
The linings of the mouth and esophagus are particularly sensitive to chemotherapy and radiation. The oral ulcerations characteristic of mucositis (also referred to as ‘stomatitis’) are a major clinical problem causing considerable pain, increased susceptibility to infection and inability to eat. Damage to the intestinal lining also occurs commonly in the small bowel, and less frequently in the large bowel, leading to severe diarrhea and pain. (Verdi C J 1993 Cancer therapy and oral mucositis. An appraisal of drug prophylaxis. Drug Safety 9:185-195; Sonis S T 1993 Oral complications of cancer chemotherapy In VT DeVita Jr., S Hellman and S A Rosenberg (ed) Cancer, Principles and Practice of Oncology, pp 2385-2394. Philadelphia, j B Lippencott Co).
In general, mucositis appears within 5 to 10 days of the drug or radiation treatment and can last several weeks. The severity of mucositis can limit subsequent doses of chemotherapy or radiation. Patients suffering mucositis may need several weeks, or more, of intravenous feeding as a result of the mouth ulcers, cramps, extreme pain, gut denuding, and severe diarrhea (Verdi 1993; Sonis 1993).
About 40% of all patients receiving chemotherapy develop significant mucositis. Incidences of up to 100% occur with some forms of chemotherapy or radiotherapy. Clinically significant mucositis develops with a range of standard chemotherapy drugs that are used, either alone or in combination, to treat various cancers including those of the colon, breast, prostate, head, neck and haemopoetic system. Examples of drugs that frequently cause direct mucositis include, but are not limited to, alkylating agents such as mechlorethamine, melphalan and busulphan, antimetabolites including cytarabine, floxuridine, 5-fluorouracil, mercaptopurine, methotrexate and thioguanine, cytotoxic drugs such as bleomycin, actinomycin-D, daunorubicin, cisplatin, etoposide, mitomycin, vinblastine and vincristine, and other chemotherapy drugs such as hyroxyurea and procarbazine (Sonis 1993). Direct exposure of the alimentary tract to high-dose radiotherapy, as occurs for example with total body irradiation, treatment of head and neck tumors or radiotherapy of abdominal tumors, will also cause a high incidence of mucositis.
One problem that is typically associated with mucositis is excessive weight loss. The damage inflicted upon the oral mucosa typically makes it painful for the patient to eat. This in turn leads to malnutrition, weight loss, and susceptibility to infections.
One current treatment for the pain associated with mucositis is oral morphine (Mayo Clinic). Oral morphine has several side effects including drowsiness, nausea, and severe constipation. These side effects can interfere with both continuation of treatment and recovery from treatment.
In addition to mucositis, loss of plasma potassium is typically associated with chemotherapy and radiation due to the diarrhea and vomiting described above. To avoid hypokalemia, potassium tablets are often given to the patient while they are undergoing chemotherapy. While these tablets minimize hypokalemia, they are very irritating to the patient's GI tract and can exacerbate the nausea and vomiting described above.
If the vomiting and diarrhea associated with chemotherapy becomes severe enough, patients can become severely dehydrated and experience electrolyte abnormalities. Such patients are often initiated on oral rehydration therapy after the occurrence of emesis and diarrhea. For example, Wadle reports that oral rehydration is typically initiated if chemotherapy patients are experiencing diarrhea, Nursing clinics of North America, December 1990, 25(4) page 901-908. Ippoliti also reports that after the occurrence of diarrhea, oral rehydration solutions should be used in cancer patients to replace any fluid loss, AM. j. Health-Syst. Pharm. August 1998 55/15 (1573-1580).
While the medical literature does describe using oral rehydration solutions (ORS) in cancer patients, their role in cancer therapy is similar to that of any patient experiencing diarrhea. ORS therapy is initiated after the onset of diarrhea and vomiting. The ORS is used to replace the water and electrolytes that the patient has lost. The medical literature does not describe the use of ORS to alleviate mucositis, especially oral mucesitits. Nor does the medical literature describe the prophylactic administration of ORS prior to the initiation of chemotherapy and/or radiation.